Modular muffler assembly and method

ABSTRACT

A modular system for muffler production and assembly allows various muffler designs to be produced from a common set of components. In particular, modular stamped muffler housing components, including two endcap designs and an intermediate body component design, can be assembled in various ways to produce muffler shells of varying length and configuration, while also ensuring high performance of the finished product. Additional components, such as crossover tubes, baffles and manifold pipes, may be integrated into a particular muffler design upon final assembly.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to Chinese Patent Application No. 201810507989.3, entitled MANUFACTURING METHOD AND MUFFLER CONSTRUCTION and filed on May 24, 2018, the entire disclosure of which is hereby expressly incorporated by reference herein.

BACKGROUND 1. Technical Field

The present disclosure relates to mufflers for combustion engines and, more particularly, to methods for efficient muffler production and mufflers made by such methods.

2. Description of the Related Art

Mufflers, also referred to as silencers, are used widely in devices which utilize internal combustion engines, such as for generator sets, construction equipment, agricultural equipment, on- and off-road vehicles, riding lawn tractors, zero-turn mowers, and garden tools, for example. Users of such devices have developed high expectations for muffler function, including noise reduction and emissions control.

Existing mufflers are typically constructed from a single-component shell manufactured by roll-crimping or welding. This shell receives internal components, such as baffles, crossover tubes and/or manifold pipes. The shell is typically enclosed at its axial ends via plate-like end caps designed to fit over the open ends and, in some cases, admit the passage of a tube therethrough (e.g., an exhaust tube for example).

While such existing muffler designs may be fit for their purpose, their cost and complexity can lead to expensive and/or time-consuming manufacturing. For example, dedicated muffler shell components may be needed for each muffler design, leading to large component inventories, material waste and low production efficiency for muffler manufacturers. In addition, component tolerances can be expensive to maintain using known manufacturing methods, particularly where a reliable restriction of airflow at component joints and junctions is required for noise reduction.

What is needed is an improvement over the foregoing.

SUMMARY

The present disclosure provides a modular system for muffler production and assembly, which allows various muffler designs to be produced from a common set of components. In particular, modular stamped muffler housing components, including two endcap designs and an intermediate body component design, can be assembled in various ways to produce muffler shells of varying length and configuration, while also ensuring high performance of the finished product. Additional components, such as crossover tubes, baffles and manifold pipes, may be integrated into a particular muffler design upon final assembly.

In one form thereof, the present disclosure provides a muffler including: a first endcap having a first annular body with a first closed end and a first open end opposite the first closed end, the first open end defining an outer periphery; a second endcap having a second annular body with a second closed end and a second open end opposite the second closed end having a lip defining an inner periphery commensurate with the outer periphery such that the lip is sealingly receivable over the first open end; a baffle configured to control a flow of gases through at least one of the first endcap and the second endcap; and a crossover tube extending through the baffle and configured to transmit at least a portion of the flow of gases from an intake port to an exhaust port of the muffler.

In another form thereof, the present disclosure provides a kit for building a muffler from a set of modular components, the kit including: a set of endcaps each having an annular body with a closed end and an open end opposite the closed end, at least a pair of the set of endcaps sealingly received upon one another; and at least one annular intermediate component sealingly receivable to the set of endcaps.

In yet another form thereof, the present disclosure provides a method of manufacturing a muffler, the method including: stamping a first muffler component from a first blank such that the first muffler component includes a first annular body with an open end and a closed end; and stamping a second muffler component from a second blank such that the second muffler component includes a second annular body with an open end and a closed end, the open end of the second muffler component sized to be sealingly received over the open end of the first muffler component.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features and objects of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a muffler assembly made in accordance with the present disclosure;

FIG. 2 is a cross-section, perspective view of the muffler assembly shown in FIG. 1, taken along line 2-2 of FIG. 1;

FIG. 3 is an exploded, perspective view of the muffler assembly shown in FIG. 1;

FIG. 4 is an elevation, cross-section view of the muffler assembly shown in FIG. 1, taken along line 4-4 of FIG. 1;

FIG. 5 is a perspective view of another muffler assembly made in accordance with the present disclosure;

FIG. 6 is a cross-section, perspective view of the muffler assembly shown in FIG. 5, taken along line 6-6 of FIG. 5;

FIG. 7 is a perspective view of yet another muffler assembly made in accordance with the present disclosure;

FIG. 8 is a cross-section, perspective view of the muffler assembly shown in FIG. 7, taken along line 8-8 of FIG. 5;

FIG. 9 is a perspective view of a muffler endcap made in accordance with the present disclosure and including apertures and a lip for assembly to other muffler components;

FIG. 10 is a left side, elevation view of the muffler endcap shown in FIG. 9;

FIG. 11 is a right side, elevation view of the muffler endcap shown in FIG. 9;

FIG. 12 is top plan view of the muffler endcap shown in FIG. 9;

FIG. 13 is a bottom plan view of the muffler endcap shown in FIG. 9;

FIG. 14 is a front, elevation view of the muffler endcap shown in FIG. 9;

FIG. 15 is a rear, elevation view of the muffler endcap shown in FIG. 9;

FIG. 16 is a perspective view of another muffler endcap made in accordance with the present disclosure, after an initial stamping process but before creation of additional features for assembly to other muffler components;

FIG. 17 is a left side, elevation view of the muffler endcap shown in FIG. 16;

FIG. 18 is a right side, elevation view of the muffler endcap shown in FIG. 16;

FIG. 19 is top plan view of the muffler endcap shown in FIG. 16;

FIG. 20 is a bottom plan view of the muffler endcap shown in FIG. 16;

FIG. 21 is a front, elevation view of the muffler endcap shown in FIG. 16;

FIG. 22 is a rear, elevation view of the muffler endcap shown in FIG. 16;

FIG. 23 is a perspective view of a riding mower incorporating a muffler made in accordance with the present disclosure; and

FIG. 24 is a perspective view of a zero-turn mower incorporating a muffler made in accordance with the present disclosure.

Corresponding reference characters indicate corresponding parts throughout the several views. Although the exemplifications set out herein illustrate embodiments of the invention, in several forms, the embodiments disclosed below are not intended to be exhaustive or to be construed as limiting the scope of the invention to the precise forms disclosed.

DETAILED DESCRIPTION

The present disclosure is directed to muffler assemblies, such as assemblies 10, 110 and 210 shown in FIGS. 1, 5 and 7 respectively, which can be modularly assembled from a set of common components including endcap 12 (FIG. 9), endcap 14 (FIG. 16) and intermediate body component 16 (FIG. 3). As described in detail below, endcaps 12 and 14 may be modularly assembled to one another with or without one or more body components 16 in order to create a muffler shell having any desired length. Other muffler components may be assembled to the modular muffler shell by creating holes or other apertures at desired locations and assembling the components to one another to create a desired finished muffler configuration. As shown in FIG. 3, such additional muffler components may include, for example, baffles 18, crossover tubes 20, and manifold pipes 30, 32. In an exemplary embodiment, endcaps 12 and 14 and body component 16 are stamped components, which provides a high level of dimensional accuracy at a minimal cost. These stamped components may be produced in bulk and stored in a blank form, such as the blank version of endcap 14 shown in FIGS. 16-22, for modification upon assembly of a muffler in a desired configuration. High production efficiency is enabled by the use of stamping for component manufacture, combined with modular assembly from stock component blanks.

Turning now to FIG. 1, muffler assembly 10 includes a pair of endcaps 12 each attached to a central, intermediate body component 16, such that the body component 16 is functionally and spatially interposed between the endcaps 12. Each endcap 12 has a cylindrical body with an open first axial end 44 (FIG. 3) and an opposing closed end 42. Each open end 44 also includes lip 40 around the opening periphery, and which extends radially and axially outwardly from the cylindrical body of the endcap 12 as shown. Lip 40 defines an inner diameter with is commensurate with the outer diameter of the adjacent cylindrical body of body component 16 (or endcap 14, as described below), such that body component 16 may be interfitted with endcap 12 to form a tight interface between the inner surface of lip 40 and the mating outer surface of body component 16. For example, lip 40 may define a transition fit or an interference fit with the cylindrical outer surface of body component 16 or endcap 14.

For purposes of the present disclosure, muffler designs having cylindrical or substantially cylindrical outer profiles are shown and described as exemplary illustrations of the principles of the present invention. However, the present methods and structures are equally applicable to non-cylindrical muffler designs, and may be applied to such non-cylindrical designs in the same manner as described herein with respect to cylindrical components (e.g., endcaps 12, 14 and body component 16). For example, muffler designs having an oval cross-section may be produced in accordance with the present disclosure. Moreover, any annular cross-sectional shape may be employed, as required or desired for a particular application. In the interest of efficiency, cylindrical components are described and shown herein, it being understood that any annular shape may take the place of the cylindrical shapes described and shown. Further, while cylindrical components define a diameter and are discussed in that context herein, non-cylindrical annular components define a periphery whose “diameter” is the diameter of the smallest circumscribing circle around that periphery. For purposes of the present disclosure, the “diameter” of a non-cylindrical annular muffler component is defined as the diameter of this circumscribing circle.

As best shown in FIG. 2, body component 16 includes closed end 50 which is stepped down to pass by lip 40 and into the inner cavity defined by the cylindrical wall of endcap 12. As further described below, the interface between the stepped-down portion of closed end 50 and the abutting inner surface of the cylindrical wall of endcap 12 may be substantially fluid-tight, such that the closed end 50 may effectively operate as a baffle. Body component 16 has an open end 52 (FIG. 3) opposite closed end 50 and sized to interfit with lip 40 of the other endcap 12 used in muffler 10. The tight fit between lips 40 and the adjacent cylindrical walls of body component 16 may create a “sealed” interface via a substantially or entirely fluid-tight fit. A substantially fluid-tight fit may be, for example a fit which allows leakage of less than 5% of gases from the shell of muffler 10 during normal operation at typical internal pressures. In addition, a fully fluid-tight seal (i.e., with zero leakage) may be affirmatively created at the interface between lips 40 and intermediate component 16 after assembly, such as by welding, application of adhesive or sealant or any other suitable sealing method. These fluid-tight seals among the shell components of muffler assembly 10 may cooperate with other fluid-tight junctions (as described below) to creates a fluid-tight inner cavity of muffler 10, which in turn promotes smooth functioning and reduces noise during operation of the muffler.

Turning now to FIGS. 2-4, muffler 10 includes various internal and external components designed to facilitate the flow of exhaust gases through the muffler shell. Some or all of these components may also provide for noise reduction and back pressure modulation as the gases pass through muffler 10. In the illustrated embodiment, gases enter the interior cavity defined by the shell of muffler 10 via a pair of manifold pipes 30 and 32, which include manifold flanges 31 at the upstream ends thereof. Flanges 31 are configured to attach to exhaust ports on an internal combustion engine, such that exhaust gases are conveyed by manifold pipes 30, 32 into muffler 10.

These exhaust gases are then discharged into respective intake ports of the separate chambers defined by the respective endcaps 12. The left endcap 12 (as viewed in FIG. 2) defines a left intake chamber having an intake aperture 46 (FIG. 3), through which gases are received from pipe 30. The left chamber is separated from the central chamber by closed end 50 of body component 16 (FIG. 3), which is integrally formed together with the cylindrical body portion of component 16 as part of a monolithic component. Closed end 50 includes apertures 26 formed therethrough to facilitate a controlled flow of gases from the left intake chamber to the intermediate chamber defined by body component 16. The baffle portion of body component 16, at closed end 50, has an exterior periphery abutting the adjacent interior wall of endcap 12, thereby creating a partial or complete seal which may also be supplemented by the weld or other sealant applied at lip 40. In this way, closed end 50 serves the function of an interior baffle.

For the right intake chamber defined by the right endcap 12, gases are received from pipe 32 via an intake port at aperture 46 (FIG. 3). The gases then pass into the intermediate chamber of body component 16 via a separate baffle component 18 sealingly received within body component 16. Baffle 18 has a similarly plurality of apertures 26 therethrough to control the flow of gases from the right endcap chamber into the intermediate chamber, similar to apertures 26 formed in closed end 50 of body component 16. In the illustrated embodiment, the exterior periphery of baffle 18 abuts the adjacent interior wall of intermediate component 16, and may create a fluid-tight seal therewith in some applications.

The use of baffle(s) 18, and/or the baffle configuration formed in closed end 50 of body component 16, is shown and described herein for illustration of certain exemplary internal muffler configurations, it being understood that other configurations may be used as required or desired for a particular application. For example, some mufflers made in accordance with the present disclosure may exclude baffles which abut the outer muffler shell, and instead include “tube-in-tube” type baffles in which muffler chambers are formed between at least two coaxial tubes of differing diameters.

Gases discharged to the intermediate chamber from the left and right intake chambers then pass into crossover tube 20 via an array of apertures 22 formed therein. In the exemplary embodiment of FIGS. 2-4, apertures 22 may be louvered, and one end of crossover tube 20 is formed as a closed crimped end 24. As described below, these features facilitate efficient production of crossover tube 20, while ensuring that gases flow into crossover tube 20 from the intermediate chamber and out of muffler 10 via exhaust port 25. As best seen in FIGS. 2 and 4, crossover tube 20 extends through central apertures formed in baffle 18 and in the closed end 50 of body component 16, and is substantially sealingly engaged with these central apertures such that gases are substantially directed to pass between internal chambers primarily through baffle apertures 26. In this way, baffle 18 and the baffle created by closed end 50 primarily control the flow of gases between the interior chambers of the shell of muffler 10, while crossover tube 20 extends through baffle 18 and the baffle portion of body component 16 to receive a flow of gases from the shell interior and transmit the flow to the ambient area outside the muffler 10.

In some embodiments, crossover tube 20 may be omitted. In these embodiments, gases are allowed to flow from chamber to chamber and to the ambient area outside the muffler shell via perforations, such as holes through internal baffles and/or perforations and/or holes formed in the muffler shell itself.

Turning now to FIG. 3, the respective endcaps 12 are adapted from a blank form (described further below) to their differing roles at opposing ends of muffler 10 by processing each blank form differently. In particular, the left endcap 12 (as viewed in FIG. 2) includes radial aperture 46 formed within the cylindrical sidewall thereof, and sized to receive a downstream end of manifold pipe 30. In the illustrative embodiment of FIG. 3, the longitudinal axis AP of radial aperture 46 and the downstream end of pipe 30 is spaced from the central longitudinal axis AM defined by the cylindrical body of endcap 12 (and by the muffler shell more generally, after assembly). Thus, radial aperture 46 takes on an egg shape, as best illustrated in FIG. 13. In other embodiments (not shown), the longitudinal axis AP of radial aperture 46 may intersect with the central longitudinal axis AM, producing a more circular shape. Moreover, longitudinal axis AP may intersect central axis AM, or may be spaced from central axis AM by any amount as required or desired for a particular application.

By contrast, the right side endcap 12 includes both radial aperture 46, which has a similar but mirror-image position and configuration to the left side endcap 12, but further includes axial aperture 48 formed in closed end 42 and sized to sealingly receive crossover tube 20 as shown in FIGS. 2 and 4. Closed end 42 of the left side endcap 12 is allowed to remain completely sealed, as best seen in FIGS. 2 and 4. Advantageously, and as further described below, endcaps 12 may be identical components prior to the formation of apertures 46 and/or 48, such that endcaps 12 can each be drawn from a common inventory of stamped endcap components and then modified to suit their individual functions within a larger muffler configuration, such as muffler assembly 10.

In one exemplary embodiment, a reinforcement place 36 (FIG. 3) may be provided at the interior or exterior of the cylindrical wall of endcap 12 about radial aperture 46. Reinforcement plate 36 is placed against the cylindrical wall of endcap 12 and bonded thereto, such as by welding, adhesives, mechanical fasteners, or any other suitable fixation method. Reinforcement plate 36 effectively thickens the cross-sectional wall thickness of the cylindrical body in the vicinity of aperture 46. This thickening spreads forces on the cylindrical wall of endcap 12 by manifold pipes 30 and/or 32 after assembly of muffler 10 and during its operational service. This spreading of forces, in turn, reduces the stresses experienced by the cylindrical wall of endcap 12 at and around the junction between apertures 46 and pipe 30 or 32. This reduction in stress may prevent any deformation of the material around apertures 46, such that the sealed, fluid-tight connection between pipes 30, 32 and apertures 46 is maintained even when muffler 10 is installed and/or experiences bumping or jostling during operational service. Although reinforcement plate 36 is placed in the interior cavity of endcap 12 in the illustrated embodiment, reinforcement plate 36 may similarly be placed along the exterior of the cylindrical body of endcap 12 with the same functional result.

Turning now to FIGS. 5 and 6 muffler assembly 110 is shown with a different configuration from muffler assembly 10 described in detail above. Mufflers 10, 110 share several common components, and components and features of muffler 110 have reference numbers which correspond to similar or identical structures of muffler 10, except with 100 added thereto for structures with modifications.

As best seen in FIG. 6, endcaps 12 are mounted to body component 16 in the same manner as muffler 10 described above. However, the internal and external components associated with muffler 110 have a different configuration. In particular, only one of endcaps 12 includes aperture 46, and only one manifold pipe 32 is connected to the muffler shell assembly. Thus, muffler assembly 110 is a type which is configured for an engine in which all cylinders exhaust to a single pipe (e.g., a single cylinder engine, or a multi-cylinder engine with header pipes that combine into a single pipe). By contrast, muffler 10 has two apertures 46 fed by separate manifold pipes 30, 32, as shown in FIG. 1 and describe above, and therefore is configured for a multi-cylinder engine.

Crossover tube 120 of muffler 110 is also configured differently from crossover tube 20. In particular, apertures 122 are formed near the closed axial end of crossover tube 120, and are therefore positioned within the muffler cavity defined by the left endcap 12 rather than the muffler cavity within body component 16 as shown in FIG. 2 and described above. Thus, gases enter muffler 110 via aperture 46, pass through apertures 26 formed in the baffle portion of body component 16, and then enter crossover tube 120 via apertures 122. These gases are then exhausted at exhaust port 125. As also shown in FIG. 6, the closed axial end of crossover tube 120 includes cap 124 to seal the axial end, rather than a crimped end such as end 24 as shown in FIG. 2. Cap 124 may be used, for example, in configurations where the apertures 122 are positioned too close to the axial end of tube 120 to make use of a crimped end.

As shown in FIG. 5, mounting bracket 34 is also included along the exterior of the shell of muffler assembly 110. Bracket 34 may be welded, riveted or otherwise fixed to the exterior of muffler 110, and may span multiple components such as endcap 12 and body component 16 as shown. Mounting bracket 34 may be used to help support the weight of muffler 110 when attached to a vehicle, for example, and may be similarly used with any muffler design in accordance with the present disclosure, including mufflers 10 and 210.

Turning now to FIGS. 7 and 8, yet another muffler assembly 210 made in accordance with the present disclosure is shown. Mufflers 10 and 210 share several common components, and components and features of muffler 210 have reference numbers which correspond to similar or identical structures of muffler 10, except with 200 added thereto for structures with modifications.

However, muffler 210 excludes body component 16 such that endcaps 12 and 14 are directly connected to one another with no intervening components. To facilitate this connection, endcap 14 excludes lip 40, as shown in FIGS. 16-20. Instead, endcap 14 includes a cylindrical body with open end 44 (FIGS. 17-20) having the same outer diameter as open end 52 of body component 16 (FIG. 3). In this way, endcap 14 may be sealingly connected to endcap 12 in the same manner as body component 16 described above, with a similarly tight fit and similar options for creating a substantially fluid tight seal.

Muffler assembly 210 includes manifold pipes 30, 32 which transmit gases from an internal combustion to the interior of muffler 210 in the same manner as described above with respect to muffler 10. However, rather than passing crossover tube 220 through closed end 42 of one of the endcaps 12, 14 (as shown and described above with respect to muffler 10 and 110), crossover tube 220 makes a 90-degree bend within the cavity of the shell of muffler 210, and then passes through a radial-type aperture 46 formed in the sidewall of endcap 14 as shown in FIG. 7, rather than an axial aperture 48 (shown, e.g., in FIG. 3). That is, exhaust port 225 exits muffler 210 radially rather than axially as described above with respect to mufflers 10 and 110. The other axial end of crossover tube 220 is closed, via crimped end 224 similar to crossover tube 20 described above. Apertures 222 are formed in a central chamber within muffler 210, with two baffles 18 used to delineate the three chambers within the internal volume of muffler 210 as shown in FIG. 8.

As noted above, mufflers 10, 110 and 210 may be assembled from a kit of standardized components which can be modularly combined in order to create a wide array of finished muffler configurations. Such a kit may include, for example, a set of endcaps 12 including lip 40, as shown in FIG. 9, but excluding any apertures 46 or 48. Thus, endcaps 12 may be stored and ready for further processing prior to integration into a variety of muffler configurations. In particular, endcaps 12 may have an undisturbed cylindrical body and completely closed end 42, together with lip 40 and the associated open end 44. Similarly, endcaps 14, shown in FIG. 16 for example, may include an undisturbed cylindrical body, no lip 40, and a completely closed end 42, with open end 44 sized to be received within lip 40 of endcap 12. Intermediate body components 16 may also be provided with open end 52 (FIG. 3), a completely closed end 50 (i.e., without apertures 26 or a central aperture for receiving a crossover tube), and an undisturbed cylindrical body extending between the open and closed ends 52, 50. In an exemplary embodiment, the cylindrical body of endcap 14 and body component 16 have the same outer diameter at their respective open ends 44 and 52, such that either endcap 14 or body component 16 may be modularly mated to endcap 12 via lip 40 as described and shown herein.

With a set of endcaps 12, 14 and body component(s) 16, any length of muffler shell can be created. Thus, a particular internal muffler volume and overall muffler size may be modularly created from “off-the-shelf” components without the need to design or produce dedicated components for a particular muffler design. In addition to the direct use of endcaps 12, 14 and body component(s) 16, these components may be cut shorter to modify the overall dimensions and characteristics of the finished shell assembly. In addition, dedicated sets of endcaps 12, 14 and body component(s) 16 may be provided for various nominal muffler shell diameters, e.g., a set of 4-inch nominal components may be used to modularly create various 4-inch muffler shells, a separate set of 6-inch nominal components may be used to modularly create various 6-inch muffler shells, and so on. By using the modular kit to define the length and size of the muffler shell, the overall internal volume of the muffler can be modularly defined upon final assembly from the “off-the-shelf” parts described herein.

Baffles 18 and tube stock sized to create crossover tubes 20, 120 or 220 (or other crossover tube designs), may also be stocked as part of the modular muffler assembly kit. As described above, baffles 18 may be used as needed to delineate the inner chambers of any muffler configuration, either alone or in combination with the baffle portion of body component 16, if the desired muffler design includes body component 16. Different sizes of baffles 18 may be included in the kit to fit the various nominal sizes of muffler shells.

Similarly, the tube stock included with the modular muffler kit may be appropriately sized to sealingly connected to the central apertures formed through baffles 18, closed end 50 of body component 16, or axial aperture 28 through closed end 42 of endcaps 12 or 14. Different tube stock sizes may be stocked for the various nominal muffler diameters provided for in the modular muffler kit, as appropriate. When a user of the kit is ready to modularly create a finished muffler, an aperture or an array of apertures may be created through the exterior surface of a piece of the tube stock at an appropriate axial location and in an appropriate array. In the illustrated embodiment, crossover tubes 20, 120 and 220 all include louvered apertures 22, 122, 222 which can be created by a piercing tool at any axial location and in any array pattern quickly and efficiently in accordance with the needs of a particular muffler configuration. In addition, a crimped end, such as crimped end 24, may be put into an axial end of any crossover tube where the design permits enough free axial end space for crimping, or alternatively, caps 124 (FIG. 6) may be used where apertures (e.g., apertures 122) are too close to the axial end to create a crimped end.

As noted above, endcaps 12, 14 and body component 16 may be stamped components. That is, blanks may be provided which are sized and configured to be stamped into a cylindrical die to create the basic stamped shape of endcap 12, endcap 14 or intermediate body 16. In the case of endcaps 12 and 14, the stamping dies may include a bottom surface configured to create closed end 42 with the distinctive design of stepped surfaces shown in FIG. 16, and the substantially cylindrical outer shell extending from closed end 42 to open end 44. For endcap 12, lip 40 may also be formed by a separate stamping operation. Apertures, such as radial apertures 46 and/or axial apertures 48, may be subsequently pierced using a separate stamping operation, or other piercing or machining operations.

In the case of intermediate body component 16, the bottom of the stamping die may include a step for creation of the baffle portion of closed end 50 described in detail above. Apertures 26 and/or a central aperture sized to sealing receive a crossover tube (such as crossover tube 20 shown in FIG. 2) may be created using a separate stamping operation, or other piercing or machining operations.

Advantageously, the stamping operations described above provide a high degree of dimensional precision and accuracy, particularly at the open ends of the various components and around lip 40 of endcap 12. This allows the various components to be mated to one another as described above with a high degree of coaxiality and a tight interface therebetween, such as a transition fit or interference fit. This tight fit can then create an affirmative fluid-tight seal by welding, adhesives, sealant or the like around the periphery of lip 40, as described above. During assembly, mating components of the muffler shell are pressed together to seat the axial end of one piece (e.g., endcap 14 or intermediate component 16) firmly against the interior shoulder formed at the inner end of lip 40 (e.g., of endcap 12). When so assembled, the components become aligned with a high degree of coaxiality.

Endcaps 12, 14 and intermediate component 16 have an axial extent long enough to serve as components which defined the interior volume of the muffler shell, as opposed to traditional endcaps which merely close the axial end of an interior volume formed by a separate (non-stamped) shell component. In the illustrated embodiment, for example, endcaps 12, 14 and intermediate component 16 all define a ratio of axial depth to overall diameter which is between 0.5 and 1.5. That is, the axial depth of endcaps 12, 14 and intermediate component 16 is at least half of its diameter, and may be as large as 1.5 times its diameter. This contrasts with an endcap used in a traditional muffler design, which would define a depth:diameter ratio much less than 0.5.

In one embodiment, the outer components of muffler assembly 10, such as endcaps 12, 14 and body component 16, are formed from aluminized steel. Painted, coated or plated cold rolled steel may also be used as required or desired for a particular application. A stainless steel material may also be used, providing the best corrosion and weather resistance for a long service life in outdoor environments.

Mufflers made in accordance with the present disclosure may be used on any vehicle or other equipment using an internal combustion engine. For example, in one particular exemplary embodiment shown in FIG. 23, muffler 210 may be mounted to riding lawn mower 300 having engine compartment 302 in front of operator controls 304 and operator seat 306. Muffler 210 is mounted below the engine compartment 302 and directs exhaust fumes downwardly. The operator controls wheels 308 and mower deck 310 of mower 300 from seat 306.

In another particular exemplary embodiment shown in FIG. 24, mufflers 10 or 110 may be mounted to a zero-turn type mower 400 having engine compartment 402 behind operator controls 404 and operator seat 406. Mufflers 10 or 110 is mounted at the rear of the engine compartment 302 and directs exhaust fumes backwardly. The operator controls wheels 408 and mower deck 410 of mower 400 from seat 406.

While this invention has been described as having an exemplary design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. 

What is claimed is:
 1. A muffler comprising: a first endcap having a first annular body with a first closed end and a first open end opposite the first closed end, the first open end defining an outer periphery; a second endcap having a second annular body with a second closed end and a second open end opposite the second closed end having a lip defining an inner periphery commensurate with the outer periphery such that the lip is sealingly receivable over the first open end; a baffle configured to control a flow of gases through at least one of the first endcap and the second endcap; and a crossover tube extending through the baffle and configured to transmit at least a portion of the flow of gases from an intake port to an exhaust port of the muffler.
 2. The muffler of claim 1, wherein the baffle abuts an interior wall of one of the first annular body and the second annular body.
 3. The muffler of claim 1, further comprising an annular intermediate component interposed between the first endcap and the second endcap, the lip of the second endcap sealingly received over a first mating surface of the intermediate component, and the first endcap including a second lip adjacent the first open end, the second lip sealingly received over a second mating surface of the intermediate component endcap, the first and second mating surfaces at opposing axial end portions of the intermediate component.
 4. The muffler of claim 3, wherein: the baffle is a first baffle formed as a separate component from the first endcap and the second endcap, and the annular intermediate component includes an integrally formed second baffle formed at one of the axial end portions thereof.
 5. The muffler of claim 1, wherein at least one of the first endcap and the second endcap includes a radial aperture formed through the annular body thereof, the muffler further comprising a manifold pipe connected to the annular body at the radial aperture.
 6. The muffler of claim 5, further comprising a reinforcement plate disposed about the radial aperture, the reinforcement plate configured to effectively thicken a cross-sectional wall thickness of the annular body having the radial aperture, about a connection between the manifold pipe and the annular body.
 7. The muffler of claim 1, wherein at least one of the first endcap and the second endcap includes an axial aperture formed through the closed end thereof, the crossover tube extending through the axial aperture.
 8. The muffler of claim 1, wherein at least one of the first endcap and the second endcap includes a radial aperture formed through the annular body thereof, the crossover tube extending through the radial aperture.
 9. The muffler of claim 1, wherein the baffle includes a plurality of apertures formed therethrough.
 10. The muffler of claim 9, wherein the crossover tube includes a plurality of apertures formed through a cylindrical wall thereof, and includes at least one closed axial end.
 11. The muffler of claim 1, wherein the first endcap and the second endcap are stamped components.
 12. The muffler of claim 1, wherein the first annular body of the first endcap is a first cylindrical body, and the second annular body of the second endcap is a second cylindrical body.
 13. The muffler of claim 1, wherein the first endcap defines a ratio of an axial depth of the first endcap to an outer diameter defined by the outer periphery, the ratio being between 0.5 and 1.5.
 14. The muffler of claim 1, in combination with a riding lawn tractor, the muffler assembled to the riding lawn tractor.
 15. The muffler of claim 1, in combination with a zero-turn mower, the muffler assembled to the zero-turn mower.
 16. A kit for building a muffler from a set of modular components, the kit comprising: a set of endcaps each having an annular body with a closed end and an open end opposite the closed end, at least a pair of the set of endcaps sealingly receivable upon one another; and at least one annular intermediate component sealingly receivable to the set of endcaps.
 17. The kit of claim 16, wherein the at least one annular intermediate component defines an outer diameter at its axial ends, the set of endcaps comprising: a first endcap having a first annular body with a first closed end and a first open end opposite the first closed end, the first open end defining a common outer periphery with the annular intermediate component; and a second endcap having a second annular body with a second closed end and a second open end opposite the second closed end, the second open end having a lip defining an inner periphery commensurate with the common outer periphery such that the lip is sealingly receivable over the first open end of the first endcap or over the axial ends of the annular intermediate component.
 18. The kit of claim 16, further comprising: a set of baffles configured to control a flow of gases between the set of endcaps; and a set of crossover tubes configured to extend through at least one of the set of baffles and each configured to transmit at least a portion of the flow of gases.
 19. The kit of claim 16, wherein the annular body of the set of endcaps and the at least one annular intermediate component are cylindrical.
 20. A method of manufacturing a muffler, the method comprising: stamping a first muffler component from a first blank such that the first muffler component includes a first annular body with an open end and a closed end; and stamping a second muffler component from a second blank such that the second muffler component includes a second annular body with an open end and a closed end, the open end of the second muffler component sized to be sealingly received over the open end of the first muffler component.
 21. The method of claim 20, wherein the first muffler component is a first endcap and the second muffler component is a second endcap, the first and second endcaps cooperating to define an internal volume of the muffler when the open end of the second endcap is sealingly received over the open end of the first endcap.
 22. The method of claim 21, further comprising forming a lip in the open end of the second endcap, the lip defining an inner periphery commensurate with an outer diameter of the open end of the first endcap.
 23. The method of claim 20, wherein the first muffler component is an endcap and the second muffler component is an intermediate body component, the method further comprising: stamping an additional endcap from a third blank such that the additional endcap includes a third annular body with an open end and a closed end, the open end of the additional endcap sized to be sealingly received over the closed end of the intermediate body component, such that the endcap, the intermediate body component and the additional endcap cooperate to define an internal volume of the muffler.
 24. The method of claim 23, further comprising forming a lip in the open end of the endcap and in the open end of the additional endcap, each lip defining an inner periphery commensurate with a respective outer periphery at respective axial ends of the intermediate body component.
 25. The method of claim 20, further comprising, after the steps of stamping, forming an inlet aperture and an outlet aperture in at least one of: the first annular body of the first muffler component, the closed end of the first muffler component, the second annular body of the second muffler component, and the closed end of the second muffler component.
 26. The method of claim 23, further comprising effectively thickening at least one of the first annular body and the second annular body by installing a reinforcement plate disposed about radial aperture formed therein. 